Sprwt protects you from an accepted proposal that is no longer fully signed:

• Adding a new contract with Require signature to a proposal that is Signed and Approved sends it back to Sent, so the customer has to sign the new contract and accept again.
• Switching Required on for an unsigned contract on a Signed and Approved proposal also reverts it to Sent.
• Clear Signature on a required contract of a Signed and Approved proposal reverts it to Sent.

Removing a contract does not change the status. Every one of these actions is logged (Contract added, Contract mandatory flag changed, Contract signature cleared, Status changed).